1. Field of the Invention
The present invention pertains to a process for the removal of cyanides from a cyanide-contaminated oily solid.
2. Description of the Related Art
One of the basic problems of a solvent extraction process for the decontamination of oily solid wastes is the high cyanide content remaining on the solid following solvent extraction, which content exceeds Best Demonstrated Available Technology (BDAT) standards required by the EPA. Thermal desorption, the other leading alternative for on-site waste treatment, also cannot effectively eliminate cyanides.
U.S. Pat. No. 4,239,620 discloses cyanide removal from wastewaters. The method involves contacting an activated solid upstream of a wastewater treating plant with a concentrated cyanide bearing wastewater stream at a low pH within the range of 3-6. This process, however, fails to address removing cyanides from solids.
It would be highly desirable to remove cyanides from refinery oily solid to meet BDAT standards set by the EPA so that this solid can be sent to a Class 1 landfill, or to an on-site backfill.